CAN LONG TERM DURABILITY OF CONCRETE BE PREDICTED FROM ACCELERATED TESTING
Trying to predict the long term lifetime of a concrete structure is difficult. Weexpect our structures to last for at least tens of years as structures built by the Romans nearly2000 years ago are still standing. Yet for too many modern concrete structures,maintenancecosts after only a few years can mount rapidly and may exceed the initial cost of the structurewithin its expected lifetime. Why does this happen? Many countries use accelerated methodsto assess possible lifetimes. These include wetting/drying,high temperature curing,freeze/thaw cycling as well as accelerated chemical exposure tests. The durability of concrete isnormally dictated by chemical reactions that occur within the structure. The properties ofcovercrete,the thin layer of concrete above the reinforcement,will determine the rate ofingress of deleterious species. Simply applying accelerated tests,without understanding theeffect they have on the microstructure of the cementitious binder,can lead to decisions beingtaken that do not reflect what will happen in practice. This paper discusses the use of thesetests and where they have not given satisfactory predictions of durability in a number ofcementitious composites. Investigating the microstructural and chemical changes occurring inthe cement matrix has provided the reasons why the structures have failed.
durability accelerated curing accelerated weathering composite cements
Neil B Milestone
Immobilisation Science Laboratory,Department of Engineering Materials,The University of Sheffield,Sheffield S1 3JD,United Kingdom
国际会议
The International Conference on Durability of Concrete Structures(2008年混凝土结构耐久性国际学术会议)
杭州
英文
116-125
2008-11-01（万方平台首次上网日期，不代表论文的发表时间）